Tamperproof closures for containers

ABSTRACT

A tamperproof closure for a screw neck container which comprises a closure cap carrying a catch ring which can be separated from the cap. The catch ring is located on spaced support ledges of the cap defining a support ring and inwardly directed projections of the ring extend between the ledges and engage, ratchetfashion, a ring of teeth on the container neck preventing the cap from being unscrewed. The ring has weakening points at which it can be broken so that it can be removed from the cap and the cap unscrewed. The ring is located so that its axial movement is limited and it is preferably of a colour different from the cap for distinction purposes.

United States Pate [191 Robinson Nov. 26, 1974 TAMPERPROOF CLOSURES FORCONTAINERS [75] Inventor: Peter G. Robinson, Hull, England [22] Filed:July 9,v 1973 [21] Appl. No.2 377,262

[30] Foreign Application Priority Data 2,864,521 12/1958 Kundert 215/2523,310,191 3/1967 Kern 3,464,576 9/1969 Rohde 3,532,244 10/1970 Yates215/272 Primary ExaminerDonald F. Norton Attorney, Agent, or Firm-Wo1f,Greenfield & Sacks [5 7 ABSTRACT A tamperproof closure for a screw neckcontainer which comprises a closure cap carrying a catch ring which canbe separated from the cap. The catch ring is located on spaced supportledges of the cap defining a support ring and inwardly directedprojections of the ring extend between the ledges and engage,ratchetfashion, a ring of teeth on the container neck preventing the capfrom being unscrewed.

The ring has weakening points at which it can be broken so that it canbe removed from the cap and the cap unscrewed. The ring is located sothat its axial movement is limited and it is preferably of a colourdifferent from the cap for distinction purposes.

14 Claims, 6 Drawing Figures TAMPERPROOF CLOSURES FOR CONTAINERS Thisinvention relates to the tamperproof closuring of containers wherein aclosure cap is screwed to a corresponding neck or top of a container toeffect the closing of the latter.

At present it is desirable to have, and in many cases there is, atamperproofing arrangement for such closures for ensuring that tamperingwith the container contents will not go undetected.

In one known arrangement, a closure cap is provided with a catch ringwhich is located under the cap when the latter closes the container. Thering has a plurality of ratchet projections which extend radiallyinwards of the ring and engage a ring of ratchet teeth on a peripheralregion of the container. The catch ring is connected to the cap by meansof fracture bridges which fracture when the cap is unscrewed withsufficient effort, the catch ring being prevented from rotating byvirtue of ratchet projections engaging said ratchet teeth. Thefracturing of the said bridges is a clear indication that the cap hasbeen unscrewed, intentionally or unintentionally. The said projectionsand ratchet teeth are arranged so that upon screwing on of the cap, theprojections tend to ride over the teeth when in radial overlappingrelationship therewith. Caps and their catch rings are usually mouldedintegrally in plastics material in order that the bridges can yieldresiliently as the projections ride over the ratchet teeth.

As we see it, there are several drawbacks with the known closurearrangement. One such drawback is that the cap and its ring, beingintegral, most of necessity be of the same coloured material. Anotherdrawback is that once the ring has been severed from the cap, neithercap nor ring can be used again. A third drawback is that, in our view,the design of the bridges is critical in that on the one hand they mustbe sufficiently strong as not to fracture when the cap is being screwedonto the container, and on the other hand, the bridges must besufficiently weak so that the cap can be unscrewed and the bridgesbroken without difficulty. A fourth drawback is that if the cap isunscrewed by a person who does not realise that it is a tamperproofclosure, then the bridges can be accidentally broken.

Our invention relates to a closuring arrangement having similaritieswith the known arrangement, but which, at least in its preferred form,does not suffer from the aforesaid drawbacks.

According to a first aspect of the present invention, there is provideda tamperproof closure which comprises a closure cap and a separate catchring and which is for the tamperproof closuring of a container having ascrew threaded region to which the cap may be screwed to close thecontainer and a peripheral region adjacent the screw threaded regionwhich has one or more teeth or recesses, said cap having means defininga support ring over which there is or may be placed the catch ring, andsaid catch ring having one or more inwardly directed projections whichextends or extend through the support ring so as to ride along theperipheral region of the container as the cap is being screwed theretobut to engage said tooth or teeth or recess or recesses of the containerwhen the cap closes same to prevent the cap from being unscrewed, andsaid catch ring further being adapted to be broken so that it can beremoved prior to and enabling the cap to be unscrewed from thecontainer.

Thus, the presence or absence of the catch ring is used as a means ofindicating if the container cap has been removed, although clearly thepresence of a broken catch ring on a closed container would alsoindicate tampering.

The catch ring may be adapted to be brokenby being weakened along a lineextending from edge to edge of the ring or by being slotted to provide aregion of reduced section and a tear tab may be provided as an integralpart of the ring adjacent to where it is weakened to facilitate fractureand removal of the catch ring.

The cap preferably has an outwardly directed flange ring adjacent themeans defining the support ring to prevent the catch ring from beingmoved axially of the cap and out of engagement with said teeth.

The invention in another aspect provides the container having acylindrical outlet neck which is closed by a tamperproof closure asaforesaid, said outlet having an external threaded portion to which theclosure cap is screwed, and an external peripheral region having one ormore projections or recesses engaged by the projections of the catchring, said catch ring being sufficiently restrained from axial movementrelative to the cap and outlet so that the only method of removing samefrom engagement with the teeth is by breaking same.

It will be appreciated that the cap can be used again with another catchring and the cap and catch ring are quite separate parts capable ofmanufacture by separate manufacturers. Each part is novel in itself andthe invention also provides therefore third and fourth aspects andaccording to the third aspect there is provided a closure cap for use inthe tamperproof closure as aforesaid, said cap comprising a top fromwhich depends a circular sectioned skirt and at the bottom of the skirtthere is a means forming an extension of the skirt and defining thesupport ring and having a circumferential slot or space of the or eachinwardly directed proportion of a catch ring so that the catch ring canbe slipped over the said means, and the cap further has a surfaceextending radially outwards of said means against which the catch ringabuts in being slipped over said means. The fourth aspect of theinvention provides a one-piece catch ring which has a one or moreinwardly directed projections and is adapted to be broken at aparticular location and subsequently uncoiled.

An embodiment of the present invention will now be described, by way ofexample, with reference to the accompanying drawings, wherein;

FIG. 1 is an exploded perspective view showing a container catch ringand closure cap;

FIG. 2 is a perspective view of the components of FIG. 1 when inassembled condition;

FIG. 3 is a sectional side view to an enlarged scale showing thecontainer neck when tamperproof closed by the cap and ring of FIG. 1;

FIG. 4 is a sectional elevation to an enlarged scale and taken on lineIII-III of FIG. 3; and

FIGS. 5 and 6 are respectively a side elevation and a sectionalelevation on line VIVI of FIG. 5 of part of the clamping ring.

Referring to the drawings, the closure arrangement for the neck 12 of acontainer 14 comprises basically a closure cap 16 and a catch ring 18.The closure cap 16 is adapted to be screw-threaded to a threaded region20 for the container neck to close the container. The

interior of cap 16 is provided with corresponding screw threads 16A(FIG. 3) for this purpose.

The cap 16 is generally thimble shaped insofar as it has a top 17 and askirt and at the bottom of the skirt there is a radially outwardlyextending flange 22 under which is means defining a support ring forsupporting the catch ring 18. Such means on the cap comprises arcuateseat ledges 24 with spaces 26 therebetween. Each ledge 24 has a groove24A which extends peripherally of the cap.

The catch ring 18 is of flexible material and is provided with aplurality of inwardly and obliquely directed projections 28 whichcorrespond in number and position to the spaces 26 in the cap supportring.

Additionally, the catch ring 18 has three weakened regions 30 (see FIG.5) defined by slots 30A extending into the ring but staggeredcircumferentially of the ring. Associated with each projection 28 thereis a rib 34 which is located to the inside of the ring and extendsaxially of the ring. Associated with each weakened region 30 is a fingerpull tab 36 which is located to the outside of the ring. The innersurface of the ring is provided with a peripheral rib 37 for engagingthe grooves 24A on ledges 24 as shown in FIG. 6. The ring is preferablymoulded as a one piece unit. Although three weakened regions 30 havebeen shown, it is to be appreciated that any desired number in anydesired distribution may be employed.

In use, the ring 18 slips over the support ring 24 as illustrated byarrows 38 in FIG. 1, so that the projections 28 are located in spaces 26and extend inwardly of the support ring of the cap 16. The meeting edgesof ring 18 and the ledges 24 are chamfered (as shown in FIG. 6) orrounded to facilitate slipping of the ring over the ledges. The cap andits associated catch ring 18 can now be screwed onto the threadedportion of the container 12.

Below this threaded portion 20, the container 12 is provided with aplurality of ratchet teeth 21 which are spaced round a peripheral regionlocated under threaded portion 20. It is to be noted that some 21A (FIG.4) of the teeth are only partially formed or stunted. This is becausethe container is moulded in a split mould and if the teeth were allfully formed, difficulty could be experienced in opening the mould. Theregion of ratchet teeth is bounded at the opposite side from threadedportion 20 by the shoulder of the container 14.

When the cap and its associated catch ring 18 are screwed fully home onthreaded portion 20 of the container as shown in FIGS. 2, 3 and 4, theprojections 28 are in axial overlap with the teeth 21. The cap 16 isadapted to be screwed onto container 12 by turning same in the directionindicated by arrow 42 in FIG. 1 and it will be noticed that the inclinedfaces of the ratchet teeth 21 are presented to the projections 28 sothat when the cap is being screwed on in the direction of arrow 42 theprojections 28 ride over the teeth and do not impede the screwing on thecap. If an attempt is made to unscrew the cap after the projections havestarted to ride over teeth 21, then the projections 28 engage behind theratchet teeth 21 and prevent unscrewing movement.

FIGS. 2, 3 and 4 show the cap 16 screwed fully home on the container 12with the catch ring 18 trapped between flange 22 and the containershoulder so that it cannot be moved axially relative to the ratchetteeth 21 in either direction. This is a substantial advantage of theembodiment of the invention because it makes tampering without breakingthe catch ring effectively impossible. Instead of using the containershoulder as an abutment to the ring 18, or where the container has noshoulder, e. g. in a conical container, the container neck would beprovided with an abutment flange. It will be noted that a sealing gasket44 inside and carried by cap 16 seals against the top of neck 20. Thegasket may be for example of rubber or similar material.

To open the container it is necessary first of all to break and removethe catch ring 18 by pulling of any of tabs 34, 36. When the ring isbroken at a weakened region 30, and the ring is such that this can bedone without excessive manual effort, the projections 28 can be movedradially outwards of their respective spaces 26 and the support ringremoved whereby the restraint placed on the unscrewing of the cap isremoved as the projections 28 leave engagement with ratchet teeth 21.

The ribs 34 serve the function of accurately locating the ring 18relative to the ledges 24 as shown clearly in FIG. 4.

It is to be noted that if an attempt is made to unscrew the cap 16 whenthe catch ring 18 is still present, the forces resisting unscrewing areforces set up by compression of projections 28 and not by tension on theweak regions 30. In fact, by suitable dimensioning of the cap and ring,under such unscrewing effort, the cap can be made to burst before thering 16 yeilds.

The described construction has a number of advantages particularly ascompared with the prior art arrangement previously described. Inparticular, ring 18 can be of a different colour from cap 16 making thearrangement more readily obvious that ring 18 is a tamperproof device.Secondly, because in normal use there is no rupturing in any waywhatsoever of the cap 16, it can be used again with an unbroken catchring 18.

The separating completely of the ring 18 and cap 16 obviates the needfor any bridges connecting these two pieces and therefore the previouslymentioned disadvantages of the known arrangement as relates to thebridge pieces is obviated.

Finally, the cap 16 is positively locked from being unscrewed from thecontainer by the projections 28 engaging the teeth 21. This overcomesthe risk of the seal being broken accidentally, for example, by someonetrying to unscrew the cap before they appreciate that the arrangement isintended to be tamperproof. The positive engagement further helps inpreventing the cap from unscrewing due to vibration such as may be metwhen the container is being transported. This advantage is considered tobe of considerable importance because many troubles arise becauseplastic caps work loose in transportation particularly when they arescrewed to plastics containers because of the low coefficient offriction between plastics material and plastics material.

It is preferred that the cap ring and container be constructed inplastics material although this is not absolutely essential. Thecomponent parts could, for example, be constructed from metal such astin plate, but in a preferred case, the cap is of high density polytheneand the ring is of low density polythene.

Although we have referred to items 28 of the drawings as projections anditems 22 as teeth, it is appreciated that these descriptions and,indeed, their constructions could be reversed as concerns what is formedon the inside of ring 18 and on the outside of the container neck belowthe threaded portion.

Furthermore, in a very simple arrangement, the catch ring could have asingle projection and the peripheral region could have a single toothengageable with such projection to lock the cap in position. Moreover,instead of the one or more teeth on the peripheral region of thecontainer, it may have one or more recesses into which the one or moreprojections can engage to lock the cap in position casing the container.

Tamperproof closures of the type to which the invention relates are usedin many industries. The main field of application can be summarized asthe transportation of valuable, corrosive and expensive liquid materialsin containers.

I claim 1. A tamperproof closure which comprises a closure cap and aseparate catch ring and which is for the tamperproof closuring of acontainer having a screw threaded region to which'the cap may be screwedto close the container and a peripheral region adjacent the screwthreaded region which has at least one abutment, said cap having meansdefining a support ring over which the catch ring is adapted to beplaced and said catch ring having at least one inwardly directedprojection which extends through the support ring so as to ride alongthe peripheral region of the container as the cap is being screwedthereto but to engage said abutment of the container when the cap closessame to prevent the cap from being unscrewed, and said catch ringfurther being adapted to be broken so that it can be removed prior .toand enabling the cap to be unscrewed from the container.

2. A tamperproof closure according to claim 1, wherein the catch ringhas a plurality of spaced, inwardly directed projections.

3. A tamperproof closure according to claim 2, wherein the cap has a topand a skirt portion and the means defining the support ring comprises aplurality of arcuate ledges at the edge ofthe skirt between which theprojections of the catch ring may pass.

4. A tamperproof closure according to claim 3, wherein the closure has aflange adjacent the means defining the support ring limiting the axialposition of the catch ring relative to the closure cap.

5. A tamperproof closure according to claim 4, wherein the catch ringhas a circumferential, internal rib and the ledges have an externalgroove in which said internal rib engages.

6. A tamperproof closure according to claim 1, wherein the ring isweakened by means of transverse slots therein.

7. A tamperproof closure according to claim 6, wherein the catch ringhas a finger pull tab adjacent the weakening whereby the ring may bebroken at such weakening by manual pulling of the finger pull.

8. A tamperproof closure according to claim 1, wherein the catch ring isa one piece moulding in plastics material.

9. A tamperproof closure according to claim 1, wherein the cap is aone-piece moulding in plastics material.

10. The combination of a container having a cylindrical outlet neckwhich is closed by a tamperproof closure which comprises a screw closurecap and a separate catch ring, said cap having means defining a supportring over which the catch ring is placed, and said catch ring having atleast one inwardly directed projection which extends through the supportring, the outlet neck of the container having an external threadedportion to which the closure cap is screwed, and an external peripheralregion having at least one abutment which is engaged by a projection ofthe catch ring, preventing unscrewing of the cap, said catch ring beingadapted to be broken so that it can be removed prior to and enabling thecap to be unscrewed from the container, and further being sufficientlyrestrained from axial movement relative to the cap and outlet that theonly method of removing the ring from engagement with the abutment is bybreaking the ring.

11. The combination according to claim 10, wherein the outlet neck has aplurality of spaced abutments defined by teeth on said peripheralregion, and the catch ring has a plurality of projections each engagingone of said teeth.

12. A one-piece catch ring for a tamperproof closure which has aplurality of inwardly directed projections and which is adapted to bebroken at a particular location and wherein a weakening of the ring atsaid location is created by two axial slots extending partially acrossthe width of the ring, said slots being circumferentially staggered.

13. A catch ring according to claim 12, wherein said ring is weakened atthree equi-angularly spaced locations.

14. A catch ring according to claim 12, wherein there is an externalfinger tab at each weakened location.

1. A tamperproof closure which comprises a closure cap and a separatecatch ring and which is for the tamperproof closuring of a containerhaving a screw threadEd region to which the cap may be screwed to closethe container and a peripheral region adjacent the screw threaded regionwhich has at least one abutment, said cap having means defining asupport ring over which the catch ring is adapted to be placed and saidcatch ring having at least one inwardly directed projection whichextends through the support ring so as to ride along the peripheralregion of the container as the cap is being screwed thereto but toengage said abutment of the container when the cap closes same toprevent the cap from being unscrewed, and said catch ring further beingadapted to be broken so that it can be removed prior to and enabling thecap to be unscrewed from the container.
 2. A tamperproof closureaccording to claim 1, wherein the catch ring has a plurality of spaced,inwardly directed projections.
 3. A tamperproof closure according toclaim 2, wherein the cap has a top and a skirt portion and the meansdefining the support ring comprises a plurality of arcuate ledges at theedge of the skirt between which the projections of the catch ring maypass.
 4. A tamperproof closure according to claim 3, wherein the closurehas a flange adjacent the means defining the support ring limiting theaxial position of the catch ring relative to the closure cap.
 5. Atamperproof closure according to claim 4, wherein the catch ring has acircumferential, internal rib and the ledges have an external groove inwhich said internal rib engages.
 6. A tamperproof closure according toclaim 1, wherein the ring is weakened by means of transverse slotstherein.
 7. A tamperproof closure according to claim 6, wherein thecatch ring has a finger pull tab adjacent the weakening whereby the ringmay be broken at such weakening by manual pulling of the finger pull. 8.A tamperproof closure according to claim 1, wherein the catch ring is aone piece moulding in plastics material.
 9. A tamperproof closureaccording to claim 1, wherein the cap is a one-piece moulding inplastics material.
 10. The combination of a container having acylindrical outlet neck which is closed by a tamperproof closure whichcomprises a screw closure cap and a separate catch ring, said cap havingmeans defining a support ring over which the catch ring is placed, andsaid catch ring having at least one inwardly directed projection whichextends through the support ring, the outlet neck of the containerhaving an external threaded portion to which the closure cap is screwed,and an external peripheral region having at least one abutment which isengaged by a projection of the catch ring, preventing unscrewing of thecap, said catch ring being adapted to be broken so that it can beremoved prior to and enabling the cap to be unscrewed from thecontainer, and further being sufficiently restrained from axial movementrelative to the cap and outlet that the only method of removing the ringfrom engagement with the abutment is by breaking the ring.
 11. Thecombination according to claim 10, wherein the outlet neck has aplurality of spaced abutments defined by teeth on said peripheralregion, and the catch ring has a plurality of projections each engagingone of said teeth.
 12. A one-piece catch ring for a tamperproof closurewhich has a plurality of inwardly directed projections and which isadapted to be broken at a particular location and wherein a weakening ofthe ring at said location is created by two axial slots extendingpartially across the width of the ring, said slots beingcircumferentially staggered.
 13. A catch ring according to claim 12,wherein said ring is weakened at three equi-angularly spaced locations.14. A catch ring according to claim 12, wherein there is an externalfinger tab at each weakened location.